electronic spikes effecting EFFIS

[compsci]

Since new (August 2009) my J230 has experienced electronic spikes

 

emanating from the the 3300 engine. Probably from the ignition system.

 

The spikes cause a spurious warning light with an out of limit message on my EFIS

 

such as "EGT TEMP" or "CHT TEMP". The warnings last about one second

 

and appear often. Jabiru USA has not been able to determine the cause.

 

Has this problem occured in Australian built J230s? has anyone had the

 

same experience and determined the cause?

 

For your information, U.S. built J230 use EFIS systems manufactured by

 

Grand Rapids Technology.

 

With your continuing help I will eventually get all the problems with my

 

J230 corrected.:thumb_up:

 

Compsci

 

 

[Guest ozzie]

Has the power supply lead for the EFFIS have a filter fitted? It may need one

 

 

[Captain]

Compsci

 

When I built my 230 I went for a Powermate voltage regulator as an upgrade to what I considered to be a pretty basic unit that comes with the kit.

 

Am very happy with the result.

 

I put a Dynon 180 in mine and have not noticed any spikes or performance issues with the EFIS or any other of my electronics.

 

The Powermate is made here and I suggest that you check out their website and email to Klaus if you need more data.

 

I mounted mine to the firewall and the only extra provision was to take air from the rear of the intake duct on that side and direct it onto the cooling fins on the Powermate in a similar way that J do to cool the coils. There are some pics in the thread "J230 @ YSWG".

 

Hope this is some help.

 

Regards Geoff

 

 

[jetjr]

My J200 with D180 has no obvious issues with spikes, however when throttle is backed off for descent on a hot day tacho goes crazy station 5000rpm etc, occasionally I get a high oil temp spike in cruise too

 

Unsure whats causing it

 

 

[Guest Qwerty]

Its strange that you should mention spikes Compsci. I fitted a Transponder to my new (used) Jab 3300 powered a/c recently. When I had the instrument panel out I noticed that there were (what I assume were) two large capacitors hooked to the power supply to the radio. One of the two guys that built my a/c was an electronics guy, I am guessing that he arranged his own spike protection for the radio. It might be worth persuing a simple and cost effective fix like that for your situation. It shouldn't be too hard to get informed advice about how to do it. There may even be an electronically competant member here who can help.

 

Are you happy with the J200?

 

Cheers, Qwerty.

 

 

[Tomo]

My J200 with D180 has no obvious issues with spikes, however when throttle is backed off for descent on a hot day tacho goes crazy station 5000rpm etc, occasionally I get a high oil temp spike in cruise tooUnsure whats causing it

Only happens on a hot day?

 

 

[jetjr]

Not 100% but nearly always when conditions are warmer

 

Im thinking resistors in tacho pickup line get hot in engine area and resistance drops, allowing double pickup.

 

Sometimes happens on take off out too

 

The odd "high oil pressure" alarm goes off randomly,maybe once every 3 or four hours, triggers alarm and goes straight back down - were it an analog setup it wouldnt register on the guage.

 

Of course the whole thing could be vibration and earth related and a dodgy connection somewhere. I keep checking whever Im in there

 

 

[Tomo]

I'm just thinking aloud here, and Have never seen behind the instrument panel so wouldn't know, but what would the chances of the throttle moving some wires when you pull it in and out?? Assuming you have a panel throttle...

 

Just seems to much of a coincidence to happen sometime on take off (throttle in) and descent (throttle out) for anything else...

 

A bad earth that gets moved about will do what is happening, like you suggested.

 

Just a thought i_dunno

 

 

[jetjr]

Floor throttle so unlikely

 

 

[Ballpoint 246niner]

My 120 had some pulse spiking that was easily traced to the strobe light. The guys at Jabiru always fit chokes to limit the interference, but Jamie sent me a couple more and whilst not totally fixed, it's a lot better. Fitting the chokes as close as possible to the source of the emf is the go.Hope this helps. A poor earth somewhere can also be the culprit....

 

 

[compsci]

I installed ferrite filters on all data cables to both EFIS units and the EIS

 

The EFIS and EIS are manufactured by Grand Rapids Technology.

 

I flew for over 90 minutes today without any false warning due to RF spikes. That is .... no false warnings!

 

Before installing the ferrite filters I would get many, many false warnings. Generally four or five a minute.

 

This is only the first flight after installing the filters so it may be too early

 

to declare that the problem is solved, but the change was certainly dramatic.

 

 

[Tomo]

I like the sound of that.... nice work.:thumb_up:

 

 

[jetjr]

The ferrite chokes you fitted just around the sensor cables from engine? Is this correct?

 

 

[compsci]

The ferrite chokes you fitted just around the sensor cables from engine? Is this correct?

I removed each of the three units and placed the filters on the data

 

cables. I placed them as close to the units as possible. I put filters

 

on each of the three cables connected to the primary EFIS unit; one

 

filter on the cable connected to the other EFIS unit and two or three

 

onto the EIS cables.

 

Actually I did this three weeks ago but weather, a stuck hangar door and

 

a trip to Florida delayed the flight test.

 

 

[jetjr]

Ah OK, GRT have seperate sensor modules and a data cable into EFIS?

 

If so I can see how this would workDynon D180 has all units combined, leads from engine go direct into unit

 

New Dynon Skyview has separate modules though

 

 

[Guest Andys@coffs]

Not sure if people are aware with these ferrites you can improve the effectiveness by looping the cable through the centre, around the outside, back through the centre and repeat for as much cable and or room in the center of the ferrite as you have. Ferrites like these act as an inductor, but a pretty low value one. Inductors are happy to pass DC unattenuated but act as a resistor for higher frequencies where the amount of resisting starts of very low and increase with frequency. Ferrites, as opposed to full coil inductors, are only really effective at high frequencies. The more loops around the outside the greater the inductance and therefore the lower the frequency of noise is that is reduced in signal level by the inductor. If ferrites dont work try a commercially available coil with a capacitor (use google to look for low pass filter) the coil is inline with the signal and the capacitor across the line and earth on the EFIS side of the coil. Capacitors are opposite to coils, they dont pass DC and become progressively less resistive as the frequency of applied signals increases.

 

---------

 

| EFIS |----------COIL---------source of signal

 

| .......| .........|

 

| .......| ....capacitor

 

| .......| .........|

 

| .......|--------------------Earth

 

---------

 

Andy